Degradative Events in epidermis will be investigated in order to determine if lysosomes and acid hydrolases play a determining role in selective and generalized autolysis during keratinization. Acid hydrolases and lysosomes will be characterized in keratinizing and non keratinizing epithelium. Morphological changes and metabolic markers of keratinization will be correlated with lysosomal enzymes in model systems for proliferation, keratinization and lysosomal inhibition. Hydrophobic lipids are generated from endogenous fatty acids as phospholipids are hydrolyzed during keratinization; the disposition of these moieties will be investigated.